Printed document control with verified unique watermarks

ABSTRACT

Systems and methods are directed towards generating a verified unique watermark. More specifically, the systems and methods are directed towards generating a watermark that is as long as possible without any repetition. Such watermarks are possible by selecting characteristics of the watermark and methods for producing the watermarks (e.g., dandy rollers). By producing longer unique watermarks, users would be capable of generating longer rolls of paper whereby more sheets can be produced that each possesses a unique watermark. With the unique watermark, users can identify what information is printed on each sheet as well as authenticate the contents of each individual sheet.

BACKGROUND OF THE INVENTION

Field of Invention

The present invention generally relates to watermarks. Morespecifically, the present invention relates to watermark based printingrecords.

Description of the Related Art

Watermarks have been used as a way to validate (i.e. security feature)paper sources for valuable documents such as money and vouchers. Inparticular, watermarks are used to ensure that the document containingthe watermark is an original. The use of watermarks prevents somemethods of forgery such as photocopying since the actual watermark isnot easily replicated.

Watermarks are identifying images or patterns that are embedded withinpaper. Watermarks are generally produced through the use of the dandyroll process or the cylinder mold process during the manufacturing stageof paper. Although a dandy roller is generally a mesh drum that picks upfibers associated with the paper during manufacturing, the term dandyroller is generally referencing any roller that creates watermarks onpaper such as a cylinder mold). Based on the thickness or densityvariations in the paper, the watermarks are capable of appearing asvarious shades of light and dark when viewed by transmitted light.

By incorporating watermarks in paper, the tracking of paper can beimplemented. For example, a particular sheet of paper can be identifiedwith a particular date, size, mill (i.e. mill trademark/location) andquality.

There is a need for more sophisticated recording means useable withwatermarks. The recording means can track specifically what informationwas printed on what pages of a document. In this way, verification canbe performed to identify what information was on the pages that may havebeen previously printed and postmarked. Furthermore, verification can beused to determine what information was on pages that may have been lostor on pages that may have been substituted.

SUMMARY OF THE CLAIMED INVENTION

A method for generating verified unique watermarks is presently claimed.The method is directed towards generating longer unique watermarks thatcan be used to track information about the paper. The longer uniquewatermarks may be generated by combining two or more marks that repeatat different times. For example, the two or more different marks may beembedded onto the paper during manufacturing by using dandy rollershaving different circumferential lengths. By selecting the marks andcircumferential lengths of the dandy rollers, longer watermarks can begenerated that can subsequently be used to track more information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A-1C illustrates watermarks that are generated across paper usingdandy rollers.

FIG. 2 illustrates an overall method whereby the watermarks describedherein are generated, recorded, and used.

FIG. 3 illustrates a method for identifying the location of a particularsheet within the original paper roll.

DETAILED DESCRIPTION

The systems and methods described herein are directed towards producinga continual unique sequence of water marks usable during the manufactureof paper. The continual unique sequence of watermarks facilitates theability for individual sheets to be identified and traced.

The systems and methods described herein also utilize the uniquesequence of watermarks in recording what types of information (e.g.,document, image) that was printed on the watermarked paper. Through theuse of the recordation of what information is printed on the paper, acustomer is capable of accounting for and controlling the use of thewatermarked paper. The customer is then capable of validating theinformation printed on the watermarked paper to ensure that, forexample, the paper is an original print (i.e. not a copy, modified,substituted).

FIG. 1 illustrates watermarks that are generated across paper usingdandy rollers. In particular, FIG. 1A illustrates watermarks that aregenerated from two dandy rollers. By using two dandy rolls, a muchlonger combined watermark can be generated that will be described infurther detail below.

A continuously varying watermark may be achieved by using two or moredandy rollers (each with their own respective watermark as illustratedin FIG. 1A). Each of the dandy rollers may have different circumferencescompared to each other. With the difference in circumference associatedwith each dandy roller, each dandy roller also has a differentrotational speed. The difference in rotational speed is present becauseeach dandy roller has to achieve the same linear speed matching thespeed of the paper during manufacturing. With reference to FIG. 1A, asmaller dandy roller can be seen with the “moon” watermark while alarger dandy roller can be seen with the “sun” watermark.

It should be noted that the customer may select a variety of differenttypes of visible marks that can be used as watermarks for the paper. Forexample, shapes and barcodes can be used as visible marks. So long as aselected mark is capable of being reliably recognized and decoded forinformation (e.g., offset), the customer can select any number of marksfor use.

The information associated with the watermark may include a variety ofdifferent information. For example, the watermark used across the dandyrollers correspond to a binary representation of customer and productioninformation, offsets between the dandy rollers, digital signatures, andany sort of information regarding the roller sizes, mark sizes, lag andproperties of the paper.

Another example configuration of watermarks compared to FIG. 1A can beseen in FIG. 1B. In particular, this embodiment illustrates a situationwhere three different marks are repeated across the paper to produce oneunique watermark that can be used to identify a page. With the examplein FIG. 1B, it may be possible that by using a resolution of 0.1 mmalong with three separate marks (e.g., sun, moon, star) replicated threetimes each and repeating every 30 mm, the watermark is capable of 300binary digits that could be used to encode information across a singleline of paper. Furthermore, the three marks that are used in FIG. 1B canbe provided using smaller rollers and not necessarily full-lengthrollers (see FIG. 1C).

Since the rotational speed and the circumference of each dandy rollerare different, the rotational position of the two or more dandy rollerswill change over time or over the length of paper. In other words, eventhough the watermarks for each of the dandy rollers will begin at a“start” position, a dandy roller with a smaller circumference willcomplete a revolution before a dandy roller with a larger circumference.Therefore, subsequent cycles will be offset (i.e. the smaller dandyroller will start a second cycle before a larger dandy roller finishestheir first cycle). Returning to FIG. 1A, this can be seen where abouttwo “moon” watermarks are produced for every one “sun” watermark.

The position of each dandy roller can be determined in the combinedwatermarks of the paper produced by the two or more dandy rollers (i.e.the “sun” and the “moon” watermarks) based on the total number ofrevolutions that can be performed without repeating the watermark duringthe manufacturing of the paper. Such a calculation corresponds to atotal length of paper that can have a unique, non-repeated watermarkgenerally based on the circumferences of the rollers. In an embodimentassociated with FIG. 1A, the “sun” dandy roller has a circumference of11λ while the “moon” dandy roller has a circumference of 6λ. It shouldbe noted that when “λ” is referenced in the description and/or thefigures, the symbol “λ” is being used to represent an arbitrary unit oflength. Therefore, a maximum length for the combined and non-repeatingwatermark produced by these two dandy rollers will be 66λ (or a multipleof the circumferences of each of the dandy rollers used).

Once the 66λ has been reached, both dandy rollers will presumably reachtheir original “start” position. The watermarks produced after the 66λmark will be identical to watermarks produced prior to the 66λ mark.Therefore, once the 66λ mark has been reached, it will be no longerpossible to differentiate from paper with watermarks produced before andafter the 66λ as these watermarks are identical.

It is possible, however, that a maximum length for the combined andnon-repeating watermark produced is less than the multiple of thecircumferences of each of the dandy rollers used. For example, if twodandy rollers used are common multiples of each other (e.g., 12λ and6λ), both the dandy rollers would be at the “start” position at thepoint when the largest roller (e.g., 12λ) completes its first cycle. Inthis way, the smaller roller can be seen as beingredundant/non-beneficial.

Therefore, a more accurate representation for the calculation for themaximum length for the combined and non-repeating watermark produced bytwo dandy rollers is achieved with the multiplying of the circumferencesof the dandy rollers used in relation to the highest common factor (hcf)of the circumferences of the dandy rollers used. An equation ispresented below:Max Length=C·c/hcf(C,c)It should be noted that “C” and “c” represent the respectivecircumferences of each of the two dandy rollers used. Furthermore, thehcf( ) refers to the highest common factor associated with the twocircumferences.

In situations where the highest common factor between two circumferencesis 1 (e.g., 6λ and 11λ as illustrated in FIG. 1A), the multiplying ofthe corresponding circumferences of the dandy rollers can be performedto obtain the maximum length for the non-repeating watermark that can beachieved. However, as noted in the above example between 12λ and 6λ,situations where the highest common factor is not 1, the maximum lengthfor the non-repeating watermark that can be achieved will be less thanthe multiplying of the corresponding circumferences of the dandy rollersused.

It should be noted that the circumferences for each of the dandy rollersshould be represented using the same unit of measurement. In someembodiments, it may be preferred that the circumferences be convertedinto use with the smallest unit of measurement. Furthermore, the highestcommon factor associated with the above equation only returns integers.It should be noted that the circumferences of each of the dandy rollers,however, may be integer or non-integer.

With the above in mind, to achieve a longer total size before anyrepeat, the two circumferences for the dandy rollers (C and c) should beas large as possible while having the highest common factor between thetwo circumferences be as small as possible (preferably one). In an idealembodiment the circumferences c (circumference of a smaller dandyroller) and C (circumference of a larger dandy roller compared to c)should be related based on the following equation: c=C−δ where δ (thecircumferential difference between two dandy rollers) is kept as smallas possible. In a preferred embodiment, δ could be chosen to be anirrational number so that either C or c will be irrational. In doing so,this could prevent the patterns between the dandy rollers from everrepeating.

However, it should be noted that available processes (e.g., rollers) andphysical limitations present with the paper (e.g., thermal expansion)during the creation of the watermark may hinder the accuracy of thegenerated watermarks. In fact, there may be a physical limit withrespect to the watermark measurements that could give rise tomeasurement errors when calculating offsets between the patterns fromthe dandy rollers.

In other embodiments, a δ can be chosen so that the pattern betweendandy rollers repeats at a pre-determined point. Ideally, the δ chosenwould be within the physical limitations described above so thatindistinguishable offsets (that could give rise to measurement errors)are avoided.

A number of rotations (with respect to a particular roller) before thewatermark pattern repeats between two dandy rollers can be obtained bycalculating the max length of the pattern for both dandy rollers dividedby the size of a particular roller. In the example, as illustrated inFIG. 1A, the max length of the two dandy rollers is 66λ. To calculatehow many rotations the 11λ dandy roller would take before the patterncreated by both dandy rollers repeats, the max length of the pattern isdivided by the length of the selected dandy roller. Therefore, the 11λroller will rotate 6 times (i.e. =66λ/11λ) before the two rollers (e.g.,the 11λ and the 6λ) synchronize at the start position again therebycreating a repeating pattern again.

Other characteristics that that can be observed between two or moredandy rollers are the lead (l) and lag (Λ). In an embodiment where thewatermark is being generated by two dandy rollers, the lead is always apositive value and coincides with a remainder of the circumference ofthe smaller dandy roller (e.g., c) divided into the larger dandy roller(e.g., C). In situations where the smaller dandy roller does not divideinto the larger roller at least 2 times, the lead is equal to thecircumferential difference between the smaller dandy roller and thelarger dandy roller.

In contrast, when the lead is less than half of the circumference of thesmaller dandy roller, this lead is referred to as lag. Lag correspondsto a situation where the smaller dandy roller appears to be behindrather than ahead of the larger dandy roller. It should be noted thatthe smaller the lag is between the two dandy rollers, the morerevolutions will appear to be required in order for the two dandyrollers to re-synchronize.

The two dandy rollers (e.g., c and C) will not reach the start point oftheir pattern at the same time as the other until the lead/lag obtainedis multiplied by an integer number corresponding to the number ofrevolutions of the larger roller so that the output is an exact multipleof the circumference of the smaller dandy roller.

When the two dandy rollers re-synchronize (i.e. both dandy rollersarrive at the start position of their watermark pattern after completinga rotation at the same time), the following conditions are true: 1) Theaccumulated circumferential difference is a multiple of thecircumference of the smaller roller. 2) The accumulated lag is amultiple of the circumference of the smaller roller. 3) The number ofrotation for a roller corresponds to the calculation identified above(e.g., max length divided by the circumference of the roller).

Although the above disclosure references dandy rollers, it is possiblethat such disclosures are also applicable to other methods of providingwatermarks on paper in such as way so as to generate a longer,non-repeating watermark usable for uniquely identifying paper. Forexample, other methods for providing watermarks may include bumprollers, laser watermarks, and deposits of particles (e.g., phosphorous)or fibers into the paper. We note that the same principles describedabove for dandy rollers are also applicable to marks generated usingalternative methods as well.

Although the present application is directed towards the generation ofwatermarks on paper using dandy rollers, it should be noted that theteachings are similarly applicable for other embodiments where securityfeatures are applied during manufacturing of the paper (e.g., metalribbons with varying surface depth) that utilizes a periodic variationalong with varying features (e.g., watermarks as described herein). Thecombination of the security features and the varying features similarlyallows a manufacturer to produce a longer combination of variations thatcan be used to track information on more paper as described above.

Once the watermarks have been produced on the paper, these marks canthen be processed (e.g., scanned via an imaging device) and decoded toobtain information associated with the marks. It should be noted thatinformation associated with the marks present on the paper may berecorded as the paper is produced, cut and packaged. As described above,such information may include information about how the paper wasmanufactured or to identify particular sheets of paper with respect tothe entire roll. This information, associated with the paper, may bestored for future reference. A cover sheet or RFID tag, for example, mayfacilitate or direct a user to where the information can be found. Insome embodiments, the information can be digitally signed in order toensure authenticity of the information associated with the paper.

Equipment already exists with the ability to scan watermarks on paper.In particular, a computer system controlling such equipment may becapable of producing a graduated intensity image of the scannedwatermark. The produced image can then be subject to existing imageprocessing techniques in order to recognize images and discover encodeddata. For example, in order to obtain information about a particularsheet of paper, the computer system may need to calculate the offset ofthe watermark along the roll of the manufactured paper in order toidentify a particular piece of paper. Information about the decodedimage or watermark block along the scanned page along with a physicalposition of the image or watermark on the scanned page would be used toobtain this information.

FIG. 2 illustrates an overall method 200 whereby the watermarksdescribed herein are generated, recorded, and used. As described above,the generation of the watermarks on the paper is performed during paperproduction 210. The watermarks are produced on the roll of paper via oneor more means described above (e.g., dandy roller). As the paper isspooled, the entire watermark for the roll of paper is scanned andrecorded into memory.

During cutting and packaging 220, the entire roll of paper generated in210 is cut into separate sheets and packaged into batches. Informationabout the watermarks for each sheet of paper or batch is also recordedand stored in memory. Such information may include, for example,information about a particular batch of paper (e.g., manufacturer date,paper type, customer information, sizing of the paper). Furthermore,information may also associate where the sheets of paper are associatedalong the entire length of the original roll of paper (e.g., length,width and offsets on the original roll). As illustrated in FIG. 3, thefigure illustrates a method to identify the location of a particularsheet within the original paper roll. In particular, the informationabout the watermark(s) present on the sheet of paper, length, width andoffsets can all be used to identify where exactly the sheet of paper waslocated on the original roll of paper prior to being cut.

Returning to FIG. 2, each sheet of paper is scanned while being loadedinto a printer 230. The printer may be capable of scanning and storinginformation about the watermark into memory (e.g., printer, server). Theunique watermark associated with each sheet of paper loaded into theprinter corresponds to information about the particular page that can beretrieved from memory previously stored during the cutting and packingstep 220. In this way, a sequence/order of the sheets loaded into theprinter and later used for printing can be established.

It may be possible to utilize a printer that only accepts paper with theappropriate watermarks. In other embodiments, the printer may beinstructed to print particular documents only on appropriatelywatermarked paper.

During printing 240, the printer where the paper is loaded into may alsobe capable of associating a particular sheet's identification (via theunique watermark) with information that is printed on that particularsheet. This association may also be stored within the printer or othermemory location (e.g., server).

By using the stored information obtained during printing 240, a user candetermine what information was printed on a particular sheet at a latertime. The association made by the printer between the information andthe watermark may include an image of what was printed on the page thatcan be used for authentication purposes.

With the above method, full accountability can be provided for allpaper. The unique watermarks can be better utilized for situations wheretracking authentic copies is necessary. The use of these watermarkswould prevent forgeries. Furthermore, users would be capable ofdetermining what is printed on each piece of paper thereby capable ofdetermining whether any pages (and corresponding information included onthose pages) are missing from an entire document.

The foregoing detailed description of the technology herein has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the technology to the precise formdisclosed. Many modifications and variations are possible in light ofthe above teaching. The described embodiments were chosen in order tobest explain the principles of the technology and its practicalapplication to thereby enable others skilled in the art to best utilizethe technology in various embodiments and with various modifications asare suited to the particular use contemplated. It is intended that thescope of the technology be defined by the claim.

What is claimed is:
 1. A method for generating a verified uniquewatermark, the method comprising: selecting two or more visible marks tobe embedded into paper, wherein each of the selected marks are assignedto a unique roller of a plurality of rollers, each roller having acircumference measurement having a difference from a respectivecircumference of each other roller, and wherein the difference incircumference is an irrational number; aligning the unique rollers towhich the selected marks have been assigned; generating a combined markfrom the selected two or more visible marks assigned to the alignedunique rollers, wherein the generated combined mark is produced by theunique rollers patterning the selected marks onto the paper and reflectsthe difference in circumference being the irrational number; and storinginformation associated with the generated combined mark and the roll ofpaper onto which the generated combined mark was patterned.
 2. Themethod of claim 1, wherein the two or more visible marks include avisible image.
 3. The method of claim 2, wherein the two or more visiblemarks include computer readable images.
 4. The method of claim 3,wherein the computer readable images includes barcodes.
 5. The method ofclaim 4, wherein the barcodes include QR codes.
 6. The method of claim1, wherein the two or more visible marks corresponds to informationabout the customer and production information.
 7. The method of claim 1,wherein the two or more visible marks corresponds to information aboutthe rollers.
 8. The method of claim 7, wherein the information about therollers includes the offset of the rollers used to generate the combinedmark, roller sizes, mark sizes, and lag between rollers.
 9. The methodof claim 1, wherein the two or more visible marks corresponds toinformation about the paper.
 10. The method of claim 1, wherein the twoor more visible marks correspond to a digital signature.
 11. The methodof claim 1, wherein the number of visible marks selected is two.
 12. Themethod of claim 1, wherein the two unique rollers associated with thetwo selected visible marks have different circumferential lengths. 13.The method of claim 12, wherein the two circumferential lengths for therollers of each of the selected marks have a highest common factor of 1.14. The method of claim 1, further comprising: cutting the patternedroll of paper into individual sheets; scanning each cut sheet of paper,wherein the scanned cut sheet of paper identifies a portion of thegenerated combined mark present on the cut sheet; and storinginformation associated with each cut sheet of paper, wherein the storedinformation is grouped with other stored information associated witheach cut sheet of paper within a batch of paper.
 15. The method of claim14, further comprising: loading the cut sheet of paper into a printer,wherein the printer is capable of identifying the generated combinedmark present on the cut sheet of paper; scanning each cut sheet of paperloaded into the printer, wherein the scanning identifies the generatedcombined mark; and retrieving information associated with the identifiedgenerated combined mark.
 16. The method of claim 15, further comprising:printing information onto a particular loaded sheet of paper;associating the printed information with the identified generatedcombined mark associated with the particular loaded sheet of paper; andstoring information regarding the associated printed information and theidentified generated combined mark corresponding to the particularloaded sheet of paper.